Early detection of pregnancy after IVF and embryo transfer with hyperglycosylated HCG versus Elecsys HCG+ß assay.

RESEARCH QUESTION: Is measurement of hyperglycosylated HCG (hHCG) superior to beta-HCG (HCG+ß) for early pregnancy detection after IVF and embryo transfer? DESIGN: Blood samples were collected on day 4 (+1), 7 (+1) and 11 (+2) after embryo transfer from women aged 18-45 years undergoing first or second fresh or frozen IVF embryo transfer cycles. Biochemical pregnancy was assessed on-site by HCG determination on day 11; clinical pregnancy was assessed by ultrasound on day 21 (+4/-3). Serum hHCG (immunochemiluminometric assay) and HCG+ß (Elecsys® HCG+ß assay) concentrations were measured. Performance of hHCG and HCG+ß for predicting pregnancy was evaluated and cut-offs selected. RESULTS: In total, 155 women were enrolled and underwent IVF and embryo transfer. Area under the curve (AUC) (95% CI) on day 4 was not significantly different for hHCG (AUC 0.88; 95% CI 0.83 to 0.94) and HCG+ß (AUC 0.90; 95% CI 0.84 to 0.95), as was predictive performance on day 7 and 11, with higher AUC estimates compared with day 4. Applying cut-offs derived according to Youden's index on day 4 (hHCG, 100 pg/ml; HCG+ß, 1.30 mIU/ml), both biomarkers demonstrated high negative predictive values for ruling out pregnancy (hHCG, 83.8%; HCG+ß, 82.8%) and high positive predictive values for ruling in pregnancy (hHCG, 89.0%; HCG+ß, 84.9%) on day 21. Diagnostic performance improved from day 4 to day 11. CONCLUSIONS: Predictive performance for early pregnancy post-IVF embryo transfer of day-5 blastocysts was not significantly different for hHCG and HCG+ß; hHCG superiority over HCG+ß was not shown.